4. Equalization.

After the Levels are calibrated, there is another thing to talk about: Equalization.

What is Equalization then?
Look at the figure below. It shows an ideal frequency response, a flat response from 20 - 20000 Hz.

Trying to achive this, some tricks have to be done to handle the drawbacks of a tape and recording/playback heads.
One way of handling this is to amplify lower and higher frequencies during the recording. This has to be done to compensate
for physical laws that makes it hard to record these frequencies with a flat response.

How much it should be amplified depends on the standard you choose.
The Tascam 34B is made for the NAB standard, and below is a figure showing how frequencies are
amplified at different frequencies.
Note that different speeds are not treated in the same way.

Equalization can be checked by running a test tape manufactured for NAB equalization, and if necessary
you adjust with trim pots.
Again, a service manual is needed to know how the procedure should be carried out on your recorder.
 

Another standard for equalization is IEC.
The figure below shows what happens if you play a tape with the "wrong" equalization.
"A" shows a tape recorded with IEC equalization, that is played on a recorder with NAB equalization.
As you can see, you would get a very strange frequency response!
Equalization is the most important standard to consider if you wish to interchange tapes with other recorders.

 
 
 

TEAC A-3440

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